Closed-loop thyristor current control
System- and communication configuring D7-SYS - SIMADYN D
5-69
Edition 06.2002
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Current actual values
(-X2: z12, b12, b14 and z14)
The current can be formed in the cabinet or at the interface module.
1. Generating the actual value in the SITOR cabinet:
The current actual value is generated in the SITOR cabinet using a
shunt (e.g. LEM electronic CT) or using a
CT with load resistor and rectification and is transferred as current or
voltage signal to SE20.2-X2:b12 and z12.
The signals are converted with the load resistor at the load resistor
module –A2 (righthand component side of the SE20.2), and are
normalized by appropriately inserting the load resistors.
2. Generating the actual value on the SE20.2:
Three or two CTs in a V circuit configuration can be connected to the
SE20.2-X2 on the three-phase side of the SITOR cabinet. A load
resistor is connected across the current actual value in the plant. If the
rectification is used, the 0
Ω
resistors R3 and R9 should be removed
from the SE20.2 board and 0
Ω
resistors should be inserted for
resistors R2, R10 and R15, R8. In this case, the maximum current is 1
A.
−
When using two CTs in a V circuit configuration, the first CT is
connected to connections b12 and z12; the second CT to
connections b14 and z14.
The current actual value can also be fed from connector -X9 of the
interface module or it can also be output through a load resistor
there.
If the current actual value is not used, then the input should be
short-circuited, e.g. by jumpering R1/R2 on the load resistor
module -A2.
−
When using three CTs, a neutral point is formed in the SITOR
cabinet. The remaining three CT connections are connected to
connections -X2: b12, z12 and b14.
•
Fuse monitoring
(-X2: b16)
The external 2P24 voltage is connected to -X2:b16 via the NC contact
of the fuse monitoring.
If there is no fuse monitoring (e.g. for parallel circuit configurations),
this monitoring function can be derived from the current monitoring of
each bridge.
−
The sum signal is obtained by connecting all of the NC contacts in
parallel. Using a parallel circuit configuration of the NC contacts, a
fault signal is output if any of the bridges, connected in parallel, fail.
In this case, the current limit should be reduced, depending on the
failed bridges, using additional digital inputs of the SIMADYN D
system!
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Absolute value of the line supply voltage (-X2: d22 and d24d)
pulse suppression (-X2: b30)
1. Evaluating the absolute value of the line supply voltage via SE20.2
The synchronizing module SA60.1 generates an absolute value of the
line supply voltage |V
supply
|. This voltage signal at -X2:d22 (+), d24 (-)
and the pulse supply voltage at -X2:b30 are individually monitored
against a limit and are internally OR’ed to form an "Undervoltage"
